I Did Not Then Imagine, That After A Long Abode On The Table-Lands Of Quito And The Coasts Of Peru, I Should Become Almost As Familiar With The Abrupt Movements Of The Ground As We Are In Europe With The Sound Of Thunder.

In the city of Quito, we never thought of rising from our beds when, during the night, subterraneous rumblings (bramidos), which seem always to come from the volcano of Pichincha, announced a shock, the force of which, however, is seldom in proportion to the intensity of the noise.

The indifference of the inhabitants, who bear in mind that for three centuries past their city has not been destroyed, readily communicates itself to the least intrepid traveller. It is not so much the fear of the danger, as the novelty of the sensation, which makes so forcible an impression when the effect of the slightest earthquake is felt for the first time.

From our infancy, the idea of certain contrasts becomes fixed in our minds: water appears to us an element that moves; earth, a motionless and inert mass. These impressions are the result of daily experience; they are connected with everything that is transmitted to us by the senses. When the shock of an earthquake is felt, when the earth which we had deemed so stable is shaken on its old foundations, one instant suffices to destroy long-fixed illusions. It is like awakening from a dream; but a painful awakening. We feel that we have been deceived by the apparent stability of nature; we become observant of the least noise; we mistrust for the first time the soil we have so long trod with confidence. But if the shocks be repeated, if they become frequent during several successive days, the uncertainty quickly disappears. In 1784, the inhabitants of Mexico were accustomed to hear the thunder roll beneath their feet,* (* Los bramidos de Guanazuato.) as it is heard by us in the region of the clouds. Confidence easily springs up in the human breast: on the coasts of Peru we become accustomed to the undulations of the ground, as the sailor becomes accustomed to the tossing of the ship, caused by the motion of the waves.

The reddish vapour which at Cumana had spread a mist over the horizon a little before sunset, disappeared after the 7th of November. The atmosphere resumed its former purity, and the firmament appeared, at the zenith, of that deep blue tint peculiar to climates where heat, light, and a great equality of electric charge seem all to promote the most perfect dissolution of water in the air. I observed, on the night of the 7th, the immersion of the second satellite of Jupiter. The belts of the planet were more distinct than I had ever seen them before.

I passed a part of the night in comparing the intensity of the light emitted by the beautiful stars which shine in the southern sky. I pursued this task carefully in both hemispheres, at sea, and during my abode at Lima, at Guayaquil, and at Mexico. Nearly half a century has now elapsed since La Caille examined that region of the sky which is invisible in Europe. The stars near the south pole are usually observed with so little perseverance and attention, that the greatest changes may take place in the intensity of their light and their own motion, without astronomers having the slightest knowledge of them. I think I have remarked changes of this kind in the constellation of the Crane and in that of the Ship. I compared, at first with the naked eye, the stars which are not very distant from each other, for the purpose of classing them according to the method pointed out by Herschel, in a paper read to the Royal Society of London in 1796. I afterwards employed diaphragms diminishing the aperture of the telescope, and coloured and colourless glasses placed before the eye-glass. I moreover made use of an instrument of reflexion calculated to bring simultaneously two stars into the field of the telescope, after having equalized their light by receiving it with more or fewer rays at pleasure, reflected by the silvered part of the mirror. I admit that these photometric processes are not very precise; but I believe the last, which perhaps had never before been employed, might he rendered nearly exact, by adding a scale of equal parts to the moveable frame of the telescope of the sextant. It was by taking the mean of a great number of valuations, that I saw the relative intensity of the light of the great stars decrease in the following manner: Sirius, Canopus, a Centauri, Acherner, b Centauri, Fomalhaut, Rigel, Procyon, Betelgueuse, e of the Great Dog, d of the Great Dog, a of the Crane, a of the Peacock. These experiments will become more interesting when travellers shall have determined anew, at intervals of forty or fifty years, some of those changes which the celestial bodies seem to undergo, either at their surface or with respect to their distances from our planetary system.

After having made astronomical observations with the same instruments, in our northern climates and in the torrid zone, we are surprised at the effect produced in the latter (by the transparency of the air, and the less extinction of light), on the clearness with which the double stars, the satellites of Jupiter, or certain nebulae, present themselves. Beneath a sky equally serene in appearance, it would seem as if more perfect instruments were employed; so much more distinct and well defined do the objects appear between the tropics. It cannot be doubted, that at the period when equinoctial America shall become the centre of extensive civilization, physical astronomy will make immense improvements, in proportion as the skies will be explored with excellent glasses, in the dry and hot climates of Cumana, Coro, and the island of Margareta. I do not here mention the ridge of the Cordilleras, because, with the exception of some high and nearly barren plains in Mexico and Peru, the very elevated table-lands, in which the barometric pressure is from ten to twelve inches less than at the level of the sea, have a misty and extremely variable climate.

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